class User:
    __Country = 'China'  # 私有的静态变量

    def __init__(self, name, passwd):
        self.usr = name
        self.__pwd = passwd  # 私有的实例变量/私有的对象属性

    def __func(self):  # 私有的实例方法/私有的对象方法
        print('in Son')

    def setNum(self):
        self.__num = 1

    def printNum(self):
        print(self.__num)

use1 = User('小白', 'ABC')
# use1.printNum()
use1.setNum()
use1.printNum()
use1.__num = 2